In cable modem systems, a cable modem termination system (CMTS) at one end of a cable network typically services multiple cable modems (CMs) connected to the cable network. CMs are generally installed locally at the end user's location, and communicate with the CMTS, which may be installed at a cable company's facility. The CMTS transmits data and messages to the CMs in a “downstream” direction and receives data bursts from the CMs in an “upstream” direction.
Data over Cable Service Interface Specification (DOCSIS) is a commonly used communications protocol that defines interface requirements for CMs. DOCSIS 2.0, for example, builds upon the capabilities of DOCSIS 1.0 and DOCSIS 1.1 and adds throughput in the upstream portion of the cable system. This increased upstream data capacity enables symmetrical and time-critical services, such as videoconferencing and peer-to-peer applications. When sharing a communication channel with a CMTS, the CMs may use modulation schemes in which the modems transmit data bursts to the CMTS during designated time intervals.
CMTSs typically receive data though a number of physical ports and further distinguish between different frequencies or “channels” of data using a number of internal receivers. Current CMTSs typically have a fixed relationship between their internal receivers and the physical ports.
Certain data communications, such as Voice over Internet Protocol (VoIP), may require data blocks to be transmitted on an upstream channel on a periodic basis, such as once in every 10 ms, 20 ms, or 30 ms time interval. The same time period may be allocated to the data communications within each time interval. It is important to use each upstream channel as fully as possible. Therefore, data blocks from different data communications may be packed together as much as possible.
CM initialization requires that certain information be communicated from the CMs to the CMTS on the upstream channels. As a result, CM initialization requires a lot of bandwidth, thereby limiting the amount of data communication that can occur on the upstream channels. In the current CM initialization process, the CMTS receives the CM's capabilities (e.g., information indicating the CM's configured class of service) in a registration message that is received near the end of the CM initialization process. In some instances, the CMTS may determine, based on these capabilities, that the CM needs to be switched from its current upstream channel to another upstream channel that is better suited to handling traffic for this particular CM. In such situations, the CM may need to be rebooted to the new upstream channel. The CM then re-performs the entire CM initialization process on the new upstream channel. This can cause significant delay to the end user(s) associated with the CM.
Accordingly, there is a need to improve the CM initialization process.